高速公路预制T梁混凝土密实性控制实践研究

Study on the Compactness Control of Prefabricated T-beam Concrete in Expressway

为解决高速公路T梁预制时常出现T梁混凝土气泡及密实性的问题,基于重庆城开高速某段T梁预制施工的大量实践和验证,系统分析了T梁混凝土气泡问题产生的根源,并找到主要影响因素,结果发现水泥碱含量的变化造成混凝土流变性能差,进而致使T梁混凝土内、外气泡密集。经反复研究和实践,在不改变施工工艺及主材的条件下,通过调整外加剂改善混凝土的流变性能,从而短、平、快地解决了T梁气泡及密实性问题,以提高混凝土的耐久性能。

In order to solve the problem of bubble and compactness of T-beam concrete in the prefabrication of precast T-beam of expressway,this paper have systematically analyzed the causes of bubble problems in T-beam concrete,and have found out the main influencing factors,based on a large number of practices and verifications of the prefabrication construction of a section of T-beam in Chongqing Chengkou-Kaizhou expressway.The results show that the poor rheological properties of concrete caused by the change of cement alkali content lead to the dense bubbles inside and outside the T-beam concrete.By the repeated research and practice,under the condition of not changing the construction technology and main materials,the problems of bubble and compactness of T-beam are solved in a short,flat and fast way by adjusting the admixture to improve the rheological properties of concrete,to?improve the durability of concrete.